The previous version of the Reserve Desktop model was based on hydrology and regional parameters, which were largely based on seasonal distributions of stream flow. One recent development in Environmental Water Resource methodology is the flow stressor response method, which links the hydraulic habitat requirements of biota to the hydraulic characteristics of a channel cross-section, to specify the ecological stress conditions that will occur under different flow regimes. The core component of the model uses a desktop approach to define the characteristics of a representative channel cross-section in the absence of any detailed field surveys. Components of the model deal with hydrology, hydraulics and ecological requirements.
Following analysis of the available hydrology data, the hydraulic sub-model, generates a representative channel cross-section from the user specified geozone, flood region, catchment area and local valley slope The ecological requirements of fish are based on the Velocity Depth Guild (VDG), an approach developed to interpret ecological consequences from generic information on the stream width. One situation not catered for, is greater present day flows in one or both seasons which are greater than natural flows (as a consequence of such as irrigation releases of return flows).
The model has been compared to the Intermediate and Comprehensive Reserve Determinations and has reached a Beta version where it can be used, but with caution. A user manual (with model) is included which will be revised, once the method has been more widely tested.